# Activity 1: Graphing

### To prevent an accident you must have sufficient stopping area. In activity 1, I will discover the stopping distance under normal conditions at various speeds.

I used a table to find the points of my graph. I plugged each speed into the formula and the result was the distance it takes for the vehicle to stop.

The formula to find the stopping distance is called a quadratic function, which creates a parabola. The graph for the stopping times is shown below.

# Activity 2: Calculating

### The formulas below will determine the length of a car's skid mark on wet and dry roads at different speeds.

I plugged the skid mark length into the formula's for "s" the result is how fast the car was moving when the skid mark was created.

### Why does the speed not double when the skid mark length doubles?

The speed of the car does not double the length of the skid mark because speed does not greatly affect friction. This is a principle of physics. A skid mark is created when you slam on brakes: the friction between the rubber tire and road create heat which allows the tire to leave a print on the road. The skid mark increases in length because it takes the car slightly longer to stop when it goes faster, but it does not double because stopping distance doesn't double.

# Activity 3: Reasoning

### How fast should you be going if you're 150 feet behind the car in front of you? Lets find out!

To find out what a safe speed is for this situation, I will use the formula from activity one, d = 0.044s^2 + 1.1s I will plug 150 in as d. The result is rounded to 47 miles per hour.